Shock absorbing dolly block



Patented Aug. 8, 1950 lSHOCK ABSORBING DOLLY BLOCK Frank T. Sargent,|Clio, Mich., assgnor, by mesne assignments, to 'Fairmount Tool andForging, Inc., Cleveland, Ohio, a corporation of New York ApplicationFebruary 7, 194.7, SerialNo. 727,222

(ICI. 81 15') 2 lClaims.

My invention relates tol auto-body repair tools in general and morespecifically to a newv and improved dolly block or hand anvil for use inremoving dents and bumps from sheet metal automobile panels, such ashoods, fenders and body sections.

An object of my invention is to provide a dolly block whereinsubstantially all of the weight thereof is useful mass for service as ahand anvil.

-Another object of my invention is to provide a dolly block capableofvibrating in working relationship to a work surface being treated.

Still another object of my invention is to provide a dolly block havingthe mass thereof con# centrated near the Working face, and having aresilient handle grip member in order that the full effect of the massmay be employedto vibrate against a Work surface after being struck.

In the removing of dents and bumps from sheet metal, such as automobilepanels, hoods, fenders and body sections, the principal tools used are adinging hammer and a dolly block or hand anvil. The working surface-ofthe wholly block is Vusually so constructed that different portionsthereof will conform to the contour of different portions 'of the sheetmetal structure under repair. The dolls7 is held against one surface ofthe sheet metal while hammer blows are delivered to the opposite face ofthe metal.

Other objects and a fuller understanding of my invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawing, in which:

Figure l is a topor working face view of a dolly block constructed inaccordance with my invention;

Figure 2 is a side elevational view of the dolly block constructed inaccordance with my invention;

Figure 3 is a front view ofthe dolly block of Figuresv I and 2; y

Figure 4 is a cross-sectional vview along the lin 4-4 of Figure 3; and lFigure 5 is a cross-sectionai view alongr thev line 54-501 Figure 3.

Ibelieve my inventionwill be most readily understood if Iiirstdescribethe physical construction of the dolly block illustrated in theaccompanying drawing without attention to the rea-- sonsdictating suchconstruction, and thereafter describe" a method of its use whereby thepurpose of its construction and'v the results achieved thereby will be.readily understood- Referring to the. drawing, I illustrate oneembodiment of my' invention which is useful in. re`

2 moving irregularities in automobile fenders. However, the scope of myinvention is broader than the specific embodiment illustrated in thedrawing, and may be adapted for use with other types and shapes of toolsfor similar use.

In the embodiment of my invention illustrated in the drawings,V thereference character It refers in general to the service portion of thedolly block, and the reference character II refers to the grip portionof the dolly block. In the general construction of tools of this type inaccordance with my invention,A I have concentrated the mass-Lof theservice portion of the tool in such a manner that the center of gravityof the entire tool will lie as close as possible to a work face IZ ofthe tool, well within the body of the service portion I0. Generally, theservice portion IlII may comprise steel or iron forged to suitableshapes, but may, of course, comprise any suitable material which may bedevised for this pur'- pose. The mass and weight of the service portionI Il is made of a suitable magnitude to offsetl the shock of dinginghammers used in conjunction therewith. However, inasmuch as a tool 0fthis nature is normally held in the hand of the operator, the weightmust necessarily be small enough to bey easily held in position for usewithout unduly tiring the operators arm. Thus, although a largeresistance inertia is desirable, the mass which may be employed toaccomplish the inertia is limited by ythe physical stamina of theoperator. My invention provides for a maximum mass of material having asuitable inertia, with substantially all of the mass available toproducethe inertia eiiect desired.

I` have found that certain desirable results are accomplished byconcentrating the mass in a head with the centerof gravity near theanvil surface and providing a resilient handle to hold the mass. This isaccomplished, as illustrated in the drawing, by providing a rubber bodyI4 which serves as a handle and which may -be suitably attached to theservice portion I fl. In order to more rigidly connect the serviceportion III to the rubber body handle I4, and also, in order to providemore mass, I have provided for a protrusion I3 to extend from theservice portion III intol the rubber body handle I4. This protrusion I3'is illustrated by the dotted'line Il in the Figures 2 and 3. Also,thephysical construction of the protrusionv I3 in the specificembodiment illustrated, /may be seen in cross-sectional views in theFigures 4 and 5'. A shoulder I8 extends between theservice portion I0and the protrusion I3'. The rubber body yhandle portion I4 isi-prefer- 3ably bonded both to the shoulder I8 and to the protrusion I3. Anysuitable bonding .process may be used to bond the metal and the rubberbody handle lil together. The protrusion I3, although serving to addmass to the dolly block, affords strength to the bonding between therubber body handle I4 and the service portion IB by preventingtransverse shearing along the shoulder I8. The protrusion i3 may bemodified and reduced in any suitable mannerwithout departing from the@spirit and the scope of the present invention, provided that suitableprotection against shear stress is obtained, and proper balance of themass and center of gravity is retained.

By the provision of a service portion II] with the work face thereonbeing concentrated into one large mass, and the further provision of agrip portion comprising a resilient rubber body handle I4 on the side ofthe service portion op.- posite said work face, I have produced a dollyblock tool in which substantially all of the available mass isconcentrated near the work face, and by the inertia effect of the mass,will sufficiently offset the shock of the clinging hammer blows.V

To further accentuate the concentration of the mass near the workingface I2, in the particular embodiment illustrated, I have provided forthe service portion I!! to be formed with a toe portion I6. Thus, theparticular embodiment illustrated comprises a heel portion I5, a toeportion IS and a protrusion I3. The complete tool, of course, is thenaccomplished by adding the resilient rubber body handle I4 as described.The extended toe portion lli provides a somewhat larger work face I2than could otherwise be accomplished for the same mass, but alsopositions the center of gravity of the entire tool closer to the workface I 2.

My invention comprises a distinct advantage over prior dolly blocks inthe concentration of the mass near the work face I2, in conjunction withs the resilient rubber grip handle portion I4. The dolly blocks usuallyprovided are made to the maximum weight which is convenient for theoperator to handle. Therefore, in the type of work wherein it isdesirable to have a maximum resistance to the dinging hammer blow, thedolly block tool made in accordance with the present invention isextremely desirable. It will readily be seen, that since a maximumweight'for the dolly block is conditioned upon the maximum weight whichan operator can conveniently hold, the provisionv of a dolly block inwhich the mass is distributed rather than concentrated as I have done inthe present invention, will have neither the desirable mass effect atthe point of impact, nor the very desirable moment of inertiacharacteristics which may be attributed to the concentration of massnear the work face I2. It is of course understood, that although aydolly block of equal mass might well be provided in which the mass isdistributed away from the work face I2, this mass would have usefuleffect only when the dinging hammer blow is applied directly along anaxis of the tool. That is, in a dolly block in which the mass isdistributed, a glancing blow as applied.

by the trade, would cause the block to bounce a greater distance awayfrom the surface of the work even though the total mass were the same asprovided in the present invention. Therefore, as set forth previously,the purpose of the construction as described, is to produce-thedesirable mass and moment of inertia effect which will eliminateexcessive bounding of the dolly block tool after being struck by a,clinging hammer.

'Ihe rubber body handle grip I4v serves the pur- 4 pose of allowing theservice portion I0 to rebound several times quickly against the surfacebeing treated after the blow by the hammer. That is, as the hammer iscaused to strike the opposite face of the work from which the dollyblock is in contact, the resilient grip handle I4 depresses under theblow and quickly rebounds the working face I2 of the'service portionIfIl against the surface being treated, thereby giving an added blow,

- the vibration of which hastens the metal bumping operation. By the useof my dolly, the operator is able to exert continuous tension in holdingthe dolly block against the surface of the metal being worked withoutfear of any stretching of the metal due to a dead blow being imparted tothe metal. However, full resistance to the blow is obtained because ofthe concentrationof mass near the working surface. Furthermore, by theuse of the rubber body handle I4, the amount of kickoff normallyinherent in dolly blocks is greatly reduced, and this further tends toreduce the danger of injury to the operators hands often caused by largekick off.

The principal tools used for automotive repair work are adinging hammerand a dolly block or hand anvil. The working surface of the dolly blockis so constructed that differ-ent portions thereof will conform tothecontour of dierent portions of the sheet metal structure under repair.The dolly is held against one surface of the sheet metal While .hammerblows are deliveredV to the opposite face of the-metal. The hammer iscaused to strike the surface of the panel under repair with a glancingblow so as to rebound quickly from the surface of the metal, permittingit to vibrate. The vibration thus set up in the panel aids the damagedportion to return'to its normal die-formed shape. With the striking ofeach blow of the hammer, `the dolly is caused to kick away slightly fromthe surface of the metal, but it returns immediately because of tensionin the operators arm. If the operator holds the bumping surface ofthe-dolly against the surface of the panel with suflicient pressure toovercome the kick olf following a hammer blow, stretching of the metalresults, thereby increasing the damage and precluding the return thereofto the original form;y

A dolly block constructed in accordance with the present inventionprevents stretching of the panel as it is worked smooth by. hammer-blowsdirected against the panel with the dolly held tightly against theinside of the panel. The cushion effect provided by the rubber body I4allows the dolly to leave the panel just slightly, and instantly afterthe blow is struck, thereby minimizing the stretchingof the metal.Stretching is thus minimized to such: a small factor as compared withthe result of using conventional dollies that it is unnecessary toshrink any stretched metal later in the repairoperation. Therefore,` theefficiency of the repair operation is increased.

Although the personal skill of the operatorA is important in using dollyblock tools, a dollyblock constructed in accordance with the principlesof the present invention has inherent characteristicswhich add greatlyto the skill ofthe operator. As soon as the dolly rebounds slightly fromthe panel under the impact blow of the hammer as described, it instantlyreturns to the panel with sufficient force to further eiect the.smoothing of the panel. This return blow strikes the panel While it isstill in vibrationfrom the `hammer blow, and is the idealtiming for'thereturn -blow'l to enable it to further aid the smoothing of the panel.quick return of the dolly must be entirely performed by the operatorsarm. The operator, in attempting to quickly return the dolly of standarddesign, exerts himself to provide tension in his arms. Even this addedtension in the operators arm is insufcient to imitate the action of myimproved dolly, and a great deal of exertion is required which causesquick fatigue. Further, the material used in the cushion grip, namelythe rubber body handle l, is more easily held securely in the operatorshand than the conventional dolly made of steel or cast iron. More accurate placement of the block is thereby obtained. The natural result ismore ecient repair work and less fatigue in the iingers from graspingthe dolly block.

Dolly blocks are also used in swinging blows to drive or bump out theirregularities in panels. On occasion these blows must of necessity beof great force. The cushion of the rubber body handle I4 therebyprotects the operators hands from injury which sometimes results fromthis use. It also enables the operator to always use the dolly with itsproperly shaped working face instead of using a sledge hammer as issometimes done because of the danger of injury when using standard typedollies, Of course, the dolly with the properly performed Working faceenables the operator to bump out the panel more smoothly than ispossible with a sledge hammer, which neither has the proper shapedworking space for this operation, nor can be used with the precisionwhich is essential for producing a relatively smooth shape ready forfinishing operation.

Although I have described my invention in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by Way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts maybe resorted to without Whenusing conventional dollies, the.

departing from the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:

1. A dolly block tool comprising a body of suitable mass and Weight tooffset the shock of dinging hammer blows, said body comprising a serviceportion and a grip portion, said service portion comprising a metallicbody having a work face, said metallic body having a handle attachmentprotrusion extending from the metallic body on the side thereof oppositesaid Work face, said grip portion comprising a resilient rubber bodyhaving a cavity therein corresponding to the size and shape of saidprotrusion and having a solid rubber handle portion, said protrusionextending into the cavity of said resilient rubber body, said resilientrubber body being bonded to said service portion and protrusion.

2. A dolly block tool comprising a body of suitable mass and weight tooffset the shock of clinging hammer blows, said body comprising aservice portion and grip portion, said service portion comprising ametallic body having a Work face, a heel portion, a toe portion, and ahandle attachment protrusion, said handle attachment protrusionextending from the metallic body from the side thereof opposite saidwork face, said grip portion comprising a resilient rubber body having asolid rubber handle portion, said grip portion being bonded to saidprotrusion of the service portion.

FRANK T. SARGENT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

